Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies (MOG-Abs) are commonly associated with clinical presentations as acute disseminated encephalomyelitis (ADEM) in both adults and children and anti-aquaporin 4 antibody-seronegative neuromyelitis optica spectrum disorder (NMOSD) and related syndromes such as optic neuritis, myelitis, and brainstem encephalitis. The gene discussed is MOG; the disease is optic neuritis.